Exhaust muffler for internal combustion engines



Aug. 15, 1933. B. G. HARLEY 1,922,848

EXHAUST MUFFLER FOR INTERNAL COMBUSTION ENGINES Filed Dec. 10, 1929 2 Sheets-Sheet 1 INVENTOR ATTORNEY 2 Sheets-Sheet 2 B. G. HARLEY Filed Dec. 10 1929 EXHAUST MUFFLER FOR INTERNAL COMBUSTION ENGINES Aug. 15, 1933.

ATTORNEY Patented Aug. 15, 1933 PATENT OFFICE EXHAUST MUFFLER FOR INTERNAL COM- BUSTION ENGINES Bertron G. Harley, Saco, Maine, assignor to Edna B. Harley, Saco, Maine Application December 10, 1929 Serial No. 413,031

7 Claims. (01. 137-160) This invention relates to the minimization of the exhaust noises of an internal combustion engine. This is usually attempted on the basis of a mufiler unit comprising a chambered casing baffled in one manner or another.

Such are usually interposed in the exhaust pipe-dine and being large and heavy are placed well forward but even there the bulk, weight and heat are troublesome. Moreover, they are relatively costly.

My invention contemplates a basis of sound reduction within the exhaust pipe itself and without change thereof and on a principle under which the mufliing may be effected at or adjacent the discharge end of the pipe thus avoiding the secondary pulsations so'often built up in the after section of an exhaust pipe between the muffler and the discharge end of the exhaust pipe.

More particularly, I aim to diffuse or convert the usual gas pulsations in the exhaust pipe into a spiral uniform gas flow at the point of its emission from the exhaust pipe, at the same time doing away completely with the necessity for the familiar mufiler of larger diameter than the exhaust pipe.

By my invention I am able to provide an improved device of simple construction light in weight and one easily installed within the usual or normal exhaust pipe without change thereof. An additional advantage is my provision of a muffling device for motor boats in which all of the cooling water from the engine may be turned into the exhaust pipe, and passed through the mufiling device without undue back pressure on the engine. Said water will automatically drain out of the device after the engine has been shut down and thereby preventing freezing in cold weather. A further object of my invention is to provide external of the exhaust pipe, a gas deflector which may serve the additional purpose of aiding in the support of my gas pulsation diffuser in operative position within the usual exhaust pipe.

In the drawings:

Fig. 1 shows a sectional view of a mufliing thimble in the exhaust pipe.

Fig. 2 is an end view of thimble removed.

Fig. 3 shows a modification, illustrating a whirl lip in place of elongated apertures.

Fig. 4 is an end view of modified thimble of Fig. 3 removed.

Fig. 5 shows a still further modification.

Fig. 6 a diagrammatic sectional view showing the alinement of the twothimbles, and

Fig. '7 a further modification in general reversal of the form shown in Fig. 1.

I have indicated at 1 (Fig. 1) the engine exhaust pipe of a marine motor which may be understood as connected to receive the overflow 80 of the cooling system. Within this pipe and preferably adjacent the rear end thereof I insert a rearwardly flaring thimble 2. This is preferably of generally conic shape and may be apertured axially so as to receive a central direct stream of exhaust gases. Such an axial aperture is indicated at 3. The sides, of the thimble are apertured as by the slots 4 and adjacent these are located inwardly inclined fins or flanges 5. These are so inclined as to direct the gases which pass through the apertures 4 in a generally circumferential direction which due to the conicity of the thimble results in a spiral or vortex stream generally surrounding the more direct stream which passes through the apex aperture. The spiral movement or vortex seems to diffuse the usual gas pulsations in the exhaust'pipe to relieve the exhaust of any back pressure which might be expected to be present in view of the presence of the thimble. In this it seems to increase the velocity of the gases through the apex aperture 3 and to spread them and mix them with the gases entering through the apertures 4. Whatever may be the exact performance of these gases the result .is an elimination of practically all of the usual exhaust noises.

In order to avoid .the trapping of water in the exhaust pipe and the consequent danger of freezing I provide a slot 6 through the bottom wall of the thimble, particularly through the outer or base end of it and on the lower side so that any such water will drain directly from the exhaust pipe. This slot also permits the diametric adjustment of the muflier to the inner'bore of the exhaust pipe to which it may be attached as by rivets so that it is rigidly supported on the exhaust pipe and free from vibration. The exhaust pipe as shown projects slightly through the stern board or transom 7 of a boat and over it may be placed an end cap 8 which may be provided with a collar for the end of the exhaust pipe.

In the modified form of my invention shown in Fig. 3, I provide a member 12 as before of general conic figure axially vented as at 13,

but in this form having a long slit 14, one edge of which is slightly inturned' as at 15 to give the spiral movement to the gases passing over it.

The slot 14 is downwardly disposed in the pipe 1 and extends through the outer end of the thimble as at 16 for dial nage and for the tight fitting 01' the thimbles in the exhaust pipes.

Both the thimble of Fig. l as at 2 and the thimble 12 of Fig. 3 terminate in a cylindrical portion as at 2' and 12 respectively to get a full non-vibrating bearing on the inner face of the exhaust pipes to which the cylindrical portions are riveted or otherwise attached as at 9.

In the form shown in Figs. 3 and 4 I may, if desired, provide radial vents 17 disposed in number and capacity in accordance with the effective capacity of the slot 14 and the resultant effect of the lip 15. These are not usually necessary but as desired a few or more may 'be provided or opened up after test to accommodate the pulsation resultant which is apt to be peculiar to each motor installation. They also may be employed to bring the venting area of the thimble into at least equal capacity with the internal cross sectional area of the exhaust pipe.

In the form shown in Fig. 5 the same principles are utilized in somewhat more extended arrangement. This form is designed more particularly for aero or automotive work having a dry exhaust, but is of course adaptable to marine use by slotting as indicated.

As shown in Fig. 5 there is fitted within the exhaust pipe 1 a primary thimble 22 having an apex vent 23 and longitudinal slot 24 bailied by the deflector 25.

This thimble 22 is disposed as before with apex to meet the exhaust and rearwardly flaring. Behind this i. e. at or towards the-exhaust pipe end is .a secondary thimble 32 generally similar to the first or primary 22 but having its slot 34 circumferentially opposite with reference to the slot 24. It also has its deflector 35 in reversed disposition to that of the corresponding members 25. The use of two cone elements 22 and 32 which the exhaust gases encounter successively serve the purpose of repeatedly changing the direction of movement of the gases. In passing through the cone mufiling element 22, their direction is changed from lineal to rotary and in passing through the next encountered cone or conic thimble, their direction is changed from rotary back to lineal. My mufliing fitting has associated with it a part 36 extending externally of the pipe 1 having the double purpose of aiding in the support of the conic thimble 32, and of still further deflecting the exhaust gas while it is being emitted to the atmosphere at 33. The deflector is formed so that it presents a view from the outside of the exhaust pipe, of one or more halves of a hollow sphere.

There will be seen in Fig. 6 that a reversing of the swirl is effected and I have in effect a pair of aligned vortices one partly within the other but of reversed direction. As before the aperture areas at least equal the area of the pipe so that there is no serious or even appreciable back pressure.

The form shown in Fig. 7 is a reversed type of that shown in Fig. 1. In it the cone-like thimble 42 is reversed in that its apex end 43 attached to the gas deflecting cover plate 48 by which it is supported.

It is slotted as at 44 and has flanges 45.

In this form'I have shown the flanges 45 as out turned-because of the reversal of the direction of the thimble from that shown in Figs. 1, 3 and 5. In practice they may be disposed in either direction, or some one way and some in the opposite direction.

The operation of this invention is that the conic or cone-like thimbles act as gas pulsation difi'users to convert the vibratory pulsations of the exhaust gas into a substantially continuous flow. The second important point of operation is that the conversion takes place at the zone of emission of the gas to the atmosphere or adjacent the outlet end of the exhaust pipe. The gas travelling along the exhaust pipe, in encountering the slotted cone is diverted from a lineal path to a spiral path, and it is this change of direction of motion that diffuses or breaks up the gas pulsations.

The embodiment of Fig. 5 shows that my invention is broad enough to use more than one gas pulsation diffuser or cone-line thimble. Also Figs. 5 and '7 show the desirability of associating with my gas -pulsation diflusers, a further gas deflector at least partially external of the exhaust pipe.

It can thus be seen that I have devised a muffling mechanism readily applicable to any combustion engine exhaust pipe without changing ,or 5 modifyingthe pipe and yet a mechanism which is as efficient as any mufiler now in use.

While the invention has been described more or less specifically, it is to be understood that it is not limited to the exact forms or uses shown, as described, but such obvious modifications may be made as come within the scope of the appended claims. For instance, the muffler of this invention can be used to muffle the carburetor noises in the engine intake pipe.

I claim:

1. In combination with the end of a internal combustion engine exhaust pipe, an inserted member consisting of a flaring thimble having a slotted cylindric base flange flxed in the pipe and with its apex toward the exhaust approach and having a wall aperture having an inwardly disposed baiiie edge spirally directive of the gases within the thimble, said thimble having a vent axially of the gas vortex within the flaring thimble. 115

2. A muffler member for an exhaust pipe end consisting of a flaring thimble having a slotted cylindric base flange adapted to be fixed in the pipe and with its apex toward the exhaust approach and having a wall aperture having an inwardly disposed bafiie edge spirally directive oi the gases within the thimble.

3. A muffler member for an exhaust pipe end consisting of a flaring thimble having a slotted cylindric base flange adapted to be flxed in the pipe and with its apextoward the exhaust approach and having a wall aperture having an inwardly disposed baffle edge spirally directive of the gases within the thimble, said thimble having a vent axially of the gas vortex within the flaring thimble.

4. In combination with an internal combustion engine exhaust pipe, a multiple'of mufiler members each consisting of a flaring thimble having a 135 slotted cylindric base flange spaced in the pipe and each having a wall aperture having an inwardly disposed bafile edge spirally directive of the gases within the thimble and in staggered circumferential relation to each other.

5. In combination with an internal combustion engine exhaust pipe, a multiple of mufiler members each consisting of a flaring thimble having a slotted cylindric base flange spaced in the pipe and each having a wall aperture having an in- 145 wardly disposed baffle edge spirally directive of the gases within the thimble and in staggered circumferential relation to each other, said thimbles having a vent axially of the gas vortex'within them. 1 6. In combination in a boat, an internal combustion exhaust pipe having an outlet end, gas deflecting cone-shaped slotted muflling means insertable into said outlet end of said exhaust pipe, an exhaust deflector outside of said pipe associated with the outlet end of said pipe, and means for supporting said mufliing means from said deflector whereby said mufiling means and. said deflector can be installed in a boat.

BERTRON G. HARLEY. 

